American Assassin is a mess. Not a great way to start a review. You can probably tell where this is going.

It's the story of Mitch Rapp, played by The Maze Runner himself, Dylan O'Brien. A tragic, superhero-esque origin story sees Rapp lose the love of his life to a mass shooting on the beach. It's told in graphic detail and is likely to evoke some intense reactions from the audience. Anyone looking to escape the all too frequent tragedies on the nightly news, may perhaps skip American Assassin.

As hard as it is to watch for the first half of the film, the violence feels earned. Rapp becomes a vigilante, touring the world to stop evil, one terror cell at a time. You understand his motivations, clearly, and Dylan O'Brien gives a good portrayal of a man with 'punisher' levels of unprocessed grief.

It's also in that first half that American Assassin has one of the more interesting training montages I've seen in a while, as Rapp develops his relationship with Michael Keaton's character, Stan Hurley. This is a man who has the training style of Mr Miyagi, but the bloodlust of John Rambo.

For a while, it seemed like my worst fears about American Assassin were gone. The film had maintained my interest, given me decent characters, and interesting action. It had defied comparisons to Jason Bourne movies and other spy thrillers and become its own animal.

Unfortunately, it soon devolved into one of the least interesting movies of this kind I've seen in a long time, with a tepid second half that devours the impression made by the first.

The more American Assassin goes on, the worse it gets. It builds up a certain level of goodwill and feels like a spy thriller for the modern day, this generation's international man of mystery with an axe to grind.

It turns out to be quite the opposite, as by its end, American Assassin revisits tropes from the early 2010s, the mid- to late 2000s, and even has an ending that even the action movies of the '90s would call too extreme.

For a film that's based on a book, it's probably best that you stay home and read one.